Since 1 February 2016, Zika virus infection and the related clusters of microcephaly cases and other neurological disorders have been declared to constitute a public health emergency of international concern (PHEIC). Since 2015, and as of 10 August 2016, WHO has reported 66 countries and territories with mosquito-borne transmission, including most recently the State of Florida in the USA. As of 10 August 2016, 15 countries or territories have reported microcephaly and other central nervous system (CNS) malformations potentially associated with Zika virus infection or suggestive of congenital infection.

Between 4 August and 11 August 2016, the Florida Department of Health has reported ten additional non-travel related cases in Miami-Dade County. The Department of Health still believes that active transmission is only taking place in this previously identified one-square-mile area in Miami-Dade County. As of 11 August, the Florida Department of Health has reported 404 travel-related and 25 non-travel-related Zika infections and 57 infections in pregnant women. Media are reporting that three cases are being investigated that do not have a clear link with the one-square-mile area in Miami-Dade County, including one recent case in Palm Beach county.

New developments since the last epidemiological update

A field trial for genetically-modified mosquitoes engineered to reduce Aedes aegypti populations in Florida has been approved by the Food and Drug Administration (FDA). However, mosquitoes still need to meet state and local requirements before they can be used. If approved, the mosquitoes will be released in Key Haven, Florida.

On 9 August, a Zika-related infant death of an infant born with birth defects including microcephaly in Texas received media attention as it was the first Zika-associated-death in Texas.

On 10 August, the Cayman Islands reported the first two cases of locally-acquired Zika virus.

ECDC assessmentThe spread of the Zika virus epidemic in the Americas is likely to continue as the vectors (Aedes aegypti and Aedes albopictus mosquitoes) are widely distributed there. The likelihood of travel-related cases in the EU is increasing. A detailed risk assessment is available here. As neither treatment nor vaccines are available, prevention is based on personal protection measures. Pregnant women should consider postponing non-essential travel to Zika-affected areas.